Anthraquinone vat dyes and a process of making the same



' Patented Apr. 25, 1933' UNITED STATES- NT- F ER ROBERT J GOODRICH AND EDWARD T. nowELL, OF SOUTH MILWAUKEE, WISCONSIN,

ASSIGNORS, BY MESNE ASSIGNMENTS, TO ELI. DUPONT DE NEMOURS & COMPANY,

A CORPORATION OF DELAWARE ANTHRAQUINONE VATVDYES AND A PROCESS or AKING me SAME No Drawing. 7

This invention relates toa process of prethe following description and appended claims.

innxm ie 1 of n. s. Patent N0.'1,505,

912, there is described a process for preparing a brominatedlderivative of the product obtained by methylating oxidized dibenzanthrone. The I derivative or product thus,

prepared is apparently a brominatedmethylated dihydroxy dibenzanthrone' and is described as dyeingcotton from a vat bril liant green shades that are more yellowish than the non-halogenated dyestufi".

-We have now found that this product is not a single chemical compound, but is divisible into at least two, component \prodnets of different natures. y We have further found that these two components may be readily separated and that the separated components possess properties. quite different from each other and from the composite dyestufi. One of these components, which is hereinafter designated component A,

constitutes a vat dyestuff dyeing cotton. in

green shades decidedly more yellowish and more brilliant than the composite product.

The other component as obtained, whichis hereinafter designated component B, is also more yellowish than the composite product but its dyeings on cotton are dull and not fastto acid. We have found that component B is more valuable as an intermediate for the production of dyestufls than as a dyestufi' itself, since it can be transformed into a product which is relatively fast to acid by treatment with an alkylating agent.

From the latter fact, we conclude that component B apparently is a brominated dihydroxy dibenzanthrone, probably formed f by the demethylation of the parent material during the bromination' step.

,centration. of acid may be varied, however,

Application filed August 8, 1929. Serial No. 384,463.

The removal ofcomponent B,iwhi'ch is not fast to acid, from the composite product naturally improves the quality oftheother component as a dyestuif, It is a'surprising fact that the two components of the original dyestufl as obtained after separation Ia're" both .of a moreyellowish shade thanthe composite product, since it would be naturally expected that-one component would be more bluish to offset the increased yellow ishness of the other component.

We have found that the relative proportions'of these componentsi'in the composite product depend on the'purity ofthest rtin material, dimethoxy dibenzanthrone, and on "the particular conditions of bromination.

Nevertheless, the existence of these two'components in the above identified product is independent .ofthese two factorsandis apparently inherent in thebromina'tion step Thus, even when a dimethoxy 'dibenzanthrone, purified according to the disclosures in lines 50 to 60, page 2 of U; S. Patent No. 1,505,912, is employed for bromination according to Example 1 of the abovepatent,

the product still found to contain two" separable components as described above.

In other words, althoughusing purified dimethoxy dibenzanthrone as initial mater al,

the product-of bromination is a composite product capableof separation.

'Our process of separation of the two com- 7 ponents A. and Bcompfi'ses in its preferred. form a fractional crystallization from concentrated sulfuric acid, We have found that for best results, a. sulfuric acid of about concentration should be used and the temperature shouldbe maintainedat room temperature,say 30 C. or lower. Inthe preferred method, the insoluble component,

that is, component A, is obtained inthe 7 form of microscopic hair-like needles, comprising most probably a complex sulfuric acid compound of the dyestufi'. The ,con-

within certain limits depending upon the" "desired.v If higher concentrations of 'sulfuric acid are used say 95%, there is experienced a larger loss of the insoluble component due I. to solubility. On the other hand, if lower concentrations of -sulfuric acid are used, such :as 76%, ithe separation is not so marked. 'The, preferred concentra-' -tion of the sulfuric acid will likewise de-- pend upon :the zamountkofvdyestu'lf employed,- 3 any specific case st'arti ng' with a deiinite mixture of components, the exact con 'centration to obtain best results both with respect to the yield and iqualiity' can be found by trial. In carrying out our invention in .actual' practice, the composite'dyestu ff is" 15 dissolved inooncentrated sulfuric acidv and then partially precipitated therefromfiby the V have further found that the above process, can; be adapted for use as .a'means of isolating the brominated product directly the new dyestuffs directly infanyfdesire'd purityJ Ourprocess should not be confused with methoxy-dibenzanthrones in finely divided form dissolvingthej same in concentrated sulfuric acid and then .drowningfin water.

The latter method 'ha'sfnot' been employed to; I r I I V 5 I l0par ts of the dry brominated product the best ofour knowledge to effect the separation of components but gives bo'th com ponents in a fineis'tate of subdivision. To thekbest of our knowledge, no one has before applied our or any other "equivalent process to brominated,.methoxyldibenzanthrones and 'wefbe'lievethe. dyestuffs as obtained are new Jand'fvery useful products. I I

Our invention is furthermore not-limited the amount of bromine which has been "introduced into the molecule noris it merely a separation 'ofrthieimono di, or poly b romination products, although-to ailextent this occurs. The process is applicable with good success where the amount of bromine corresponds :to "one atom, two atoms or 'to .acid and ofgreatbrilliance and the other which dyes, Cotton dull green sliades,fn t g ztastto,acid. "J- V "Without limiting the a atar a a...

"65 specific methodythe following examples are subjected to a treatment with asulfuri'c acid j from thefbromination mass, thus obtaining" "73 parts of 60 the I form of m higher or intermediate amounts of bromine.

given. to illustrate the embodiment of our invention in its preferred form. The parts are by weight.

I r j I 10 Parts of dry brominated product as 7 obtained according to Example 1 of U. S.

Patent No. 1,505,912 are dissolvedgin .100 parts. of I sulfuric :acid; 'monohydrate at 10.

to C. 11.1parts efwater arethen add- 75 Y ed over aperiod of several hours, the temperature of-the mass being inept-below C. The crystals separating in'the' form of microscopicneedles of Bordeaux ccil er are filtered off on a suction filter and sucked so as/dry as possible. The filter cake is digestj ed with water and the crystalline precipitate is filtered and washed with water --till prac- V p tically free of acid. 'lhewashed produce; component A, maybe used-directly for"dye'-- iI g. OI" itmay "first be dried. Tt iiliesl'cotton in green shades considerably yellower than 1 the original product. To the best ofgour present knowledge, I R e 's'tantially pure broniination product of di-' 0 this. product is sub methoxy 'dibenzanthrone substantially free from the, demethylated b-y-product-Yf i Upon 'pou 'ng the filtrate from the r 'croscep'ic needles into .water, a' second;c0mv ponent is precipitated and can doeirecovered by filtration. {This product, component '13,

. r V v v v v dyes cotton in yellowish green 'shadeswh-i'chthe known process of obtaining broininated are not fast-to acid. "It can as obtained accordingto Example 1,}U.

Patent No; 1,505,912,m dissolved in. 190 5 1 0 5:

parts of 99% sulfuric aeiLwi-th cooling. H Be. sulfuric acid are "then added at 10 to ]15 C. over 'a' perio'd'of several hours. -Thexcrystals separating in] 1 another liquor needles .can "bBQWOTkGd as in Example a 1 to give a similar product.

. i 1 v Ema 212472 6 -27 parts parts of sulfuric acid '-monohydrate at about C. There a're-ithen added 0f2'2jparts of J 'iodine and 10 parts. o'f dime'th'oX-y -d-iloenfzjanthrone, obtainabl'efas described in E-xample 2 in -'U. s. r rest 1,531,261 themixture being n1aintainedv at room-tempera {ture or below. After the product has dissolved in the sulfuric. acid *-the reaction mixture is, stirred foraboutj'fl hours at '25 to C. Thereactionmixt'ure is tl-ienfBQQ v icroscopic hair-like needles 0 are filtered oif and worked-up further as "in Examplel, Theproduct; -component A, Pas obtained is practically identical with that obtained according to Examplel. The

from the. miscroscopic 1115 and poured into 1000 parts of cold water and the precipitate filtered off and washed prac tically free of acid with water.

The product is then dried. The dry, crude composite product is then treated as in Example 1 or 2. The product insoluble in the concentrated sulfuric acid, component A, gives dyeings of a much yellower green and more brilliant shade than that of any product obtainable by any known process for producing brominated methoxy dibenzanthrones. atoms of bromine, and'corresponds to dibromo dimethoxy dibenzanthrone. The analysis is: found23.35% bromine; theory 23.75% bromine.

Component B may be isolated from th strong sulfuric acid filtrate. Component B dyes cotton in green shades which are not fast to acid, but may be used for the fur-' upon drowning in .water, asecond compother production of fast vat dyestuffs.

Emample 4 perature at 20 C. or below. 15.6 parts of sodium bisulfite are then added carefully. Crystals of component A precipitate and can then be filtered off and worked up further as in Example 1. p

The product obtained is practically identical with that obtained according to Example 3. Component B may be isolated from the strong acid filtrate by further dilution of the filtrate with much water.

This second component dyes cotton in yellowish shades which are not fast to acid I but may be further used for the productionv of fast vat dyestuffs.

Example 5 3 parts of dry brominated methoxy dibenzanthrone, obtained as described in Example 3 after drowning with water, are dissolved theprocessmay be. varied through a wide range. without departing'from the princiin parts of sulfuric acid 98100% with cooling, care being taken that the temperature does not exceed about 25 C. 10 parts of glacial acetic acid are then added slowly cautiously. The Bordeaux colored *needles are filtered off on a suction filter and sucked as dry as possible. The filter cake is digested in Water, filtered again and washed practically acid free. The wet cake may be used as such or it may be dried. The product is practically identical in properties to component A obtained in Example 3.

Emample 6 5 parts of the product obtained by drying the dyestuff known commercially as It contains substantially two- Indanthrene *Brilliant Green "2 1 G Double Paste (halogen content 17.76%, calculatedas .1 bromine) are dissolved in '100'fparts of sulfuric acid (100%) at a temperature of 5;to*10 ll parts of Water are added withcooling and stirringover aperiodof about an hour. Aprecipitate formswhich when examined under the microscope shows Bordeaux colored hair-like needles. These are filtered off on a porous plate andsucked as dry as possible. The filter cakeisdigested in water, filteredyand washed acid 'free. The product so. obtained consists of p a dark purple powder :with bronzy luster halogen content of this as bromine, is 21.22%. I A. 1

The strong sulfuric acid mother liquor obtained in the first; filtration abovepgives when dry, and gives'on cotton dyeings muchfl brighter than the .original'material. -The product," calculated nent, similar to componentB in thepreceding examples.- 'Its halogen. content, cal

culated as bromine, is 145.32%.

The dyestuff,co mpon ent:=A, as for example that obtained in Example- 3,- dissolves-in concentrated sulfuric acid with a: cherry red color and in'fuming sulfuric acid with 'a'color whichremains dull orange on'='standing and which doesanotchange -;color upon addition ofboric acid. It dissolves in chloro-benzene or. nitro=benzene with .a bright yellowish green color. In contrast. to this, the compositeproduct of Example .3

before separatingjit into components. dissolves in "concentrated sulfuric acid .with a dull brown color. The component'Adye stuif dyes cotton in yellowish green shades, much yellower and much more brilliant than the known products of this series.-

In. the claims below it should be understood that' where newproducts, dyestuffs, or articles ofmanufacture are claimed, we mean to include these bodies notonly in exist when applied-to material dyed, printed or'pigmented therewith. f

We are aware that numerous details of 1. The process of separating a bromine containing methylated dihydroxy dibenzanthrone product into two "fractions, which comprises mixing said dibenzanthrone'prodnot with concentrated sulfuric. acid and sep-'-- arating one portion from the other.

2. The process of separating a bromine, containing methylated dihydroxy dibenza'nthrone product into two fractions, which substance, .but also in whatever state they comprises mixing said dibenzanthrone prod- I 1 I '."l;905;0.88

' uct 531i temperatures below 30 "Guwithcon- I :centrated sulfuric acid odtanot less rthan1Z6j% end mot iover :95' %:strength and separating one portionfrom :the othenl The process of separating aimethy-lated V rdihydroxy dibenza'nthrone iproduc't 'con'tziining bromine into two fractions, :Whiohzcomprises dissolving said dibenzanthrone "prodiuct f-in concentrated sul'fur'icgaoid above v90% i jstrength and diluting'the acid With-ran inert 3 "(diluent to approximately 90% Strength at 1 temperaturesbe1oW 30 C. to maintain-one Z of said components infsolution While effect- 7 the. precipitation of another aeomponent.

' 93 54. 51 11; prolcesshof separating ai methylmad. dih ydroX-y dibenzanthrone product- 7 containing bromine "into two components, 7 f which includes 7 trad tionally cryswHizi-ng fof ione ozfsaid Components XfITODiVQJIWiQQCOII- centra ti'ons V of' sulfuric acid and iremoving -he icrystallinej portion "from zthe mother" -r1iquor; I c i- I I 1 :5; The procese :o'f1.;prep2u5ing .a s'ub'sita-n: tially pure loromsi'nated dimethoxy zdibenzem wfi one; which comprises 7 dissolving a 'bro- ".minated "derivative 101E methylaite'd diben- Y fz r lfuricj afci'd above) 90%con- I V centra'ti'on; diluting-said acid withan i e t 1 1 U i'dilu'entljtofapproximately(90% concentration 7 I #430 and separetingthe product that precipitates In the process of preparation o-fa yelv al'owishegreen vatmdyestufi the brominej tionio'fla unethylation iproduct of di'bydroxy diben'zanthrone, the improvement WVh'idh :coulprises freeing the product irom the de- 1 methylated orsincompl'etely methylated emc- I 'tions' .by mixing'wvith concentratedsulfuric i :zxcidandzsepu atingtheinsoluble-.comp1ete1y i i methylated product from the mother liquor.

The process of prep-aringia yellowish Lgreen idyestufl Which comprises reacting 1 -d=imethoxy dibenzanthrone dissolved .in-con- H :cen'tra'ted sulfuricacid with FbrOmine untilv 'substanti;1 1-y 2' atomic 'we'ights 10f :bro-

--mine (have been absorbedper mole of Ihe dibenzanthrone Ybod-y, Slowly diluting the v' 'ooncentration oifithe acid with an inertidiluen't' unti'lm, "Bordeaux colored'pre'ci p-itate Bis 550 formed, and recovering the precipitate;

- 8. .Asanew produou a dyestuiif composed 05? substantially pure brominate'd 'dinie'thoxy 'di enzanthrone. v 9. As a new product, a dyestufi' comfposed 5 of substantially lpureidibremodiimethoxy di- I flbenzanthrone. f 3 Y In testimony whereof we have hereunto '-'subscribed' our names ait- Garrotlwille, Mid.- -Waukee*C0u=nty, WiSOOIlSiiH. f j

' "ROBERT-JJG@@DRICH{V y 7 EDWARD 

